A variety of procedures has previously been proposed for the production of shapes or objects by compaction and densification of metallic powders. The term "metallic powder " as used herein is deemed to embrace metal powders proper as they are used in powder-metallurgical procedures and also includes inorganic non-metallic powders as they are, for example, disclosed in U.S. Patent 3,622,313. In this prior art patent, densified objects from metallic powders are produced in a vitreous evacuated container of a predetermined shape corresponding to the shape of the densified object ultimately desired. Generally, according to this prior art patent, a mold or container of glass or the like vitreous material is first produced, the interior cavity or space of the mold generally corresponding to the shaped object to be produced. The size or dimension of the mold cavity is such that it considers the shrinkage which may take place during the subsequent sintering or compaction procedure. The metallic powder is then filled into this mold or container under sub-atmospheric conditions whereupon the mold or container with the metal powder contained therein is subjected to hot isostatic pressing or compaction to form the ultimate object. The patent states that due to the wide difference in thermal shrinkage of the compacted metal and the surrounding glass, the glass flakes off, leaving a glass-free densified metal form.
This prior art procedure has two important drawbacks. One of the drawbacks is that it requires the use of special glass or vitreous material, the patent listing a number of representative types of glass which are suitable for the purposes of the patent. Such glass is relatively expensive. Secondly, from an economical point of view, it is generally not practical or feasible to provide molds or containers of glass for the production of shaped objects. In any event, the expenditure which is required for this purpose is generally too high to be economically sound.